Slide rule



Feb. 8, 1955 w. J. Boos SLIDE RULE Filed Feb. 19, 1951 fil,

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United States Patent SLIDE RULE Wilfred J. Boos, Webster Groves, Mo., assignor to Acu- Rule Manufacturing Company, St. Louis, Mo., a corporation of Missouri Application February 19, 1951, Serial No. 211,752

8 Claims. (Cl. 23S-70) This invention relates generally to slide rules of the type wherein a slide is arranged to be moved longitudinally between two rails, all having indicia thereon.

In slide rules of the character referred to, it is desirable that the slide be made as freely movable as possible lengthwise of the side rails and, at the same time, that the slide retain a set position between readings from one scale to another. As heretofore constructed, any increase in retentivity of setting has been at the sacriiice of free running and vice versa.

The object of the present invention, generally stated, is to provide a slide rule wherein the slide is freely manipulatable, yet highly retentive of setting.

In order to accomplish these results and others which will be apparent to those skilled in the art as the following description proceeds, the invention contemplates that the usual tongue-and-groove connection between the slide and the rails, as well as the usual cooperating shoulders between the slide and the rails, be formed so as to conne their contact with each other substantially to a point at any given cross-section.

This is accomplished by forming the cooperating surfaces so that they are deliberately out of parallel relationship with each other.

charged with lubricant. Moreover, the invention contemplates that the side rails be fxedly connected with each other in such manner as to provide slight yieldability in the spaced relationship between said rails, and consequently the grip exerted by the rails upon the slide therebetween may be adjusted without releasing any fastening. The invention further contemplates the provision of a thumb grip on the end of the slide.

In the accompanying drawings;

Figure 1 is a plan view of one end of the front of a slide rule constructed in accordance with the present l invention;

Figure 2 is a plan View of the back of the rule shown in Figure 1, but at the opposite end;

Figure 3 is a sectional View taken along line 3-3 of Figure l;

Figure 4 is a perspective view of a portion of the tongue-and-groove connection between the slide and the side rails of the rule shown in Figure 1, said parts being broken away to reveal their cooperating relationship; and

Figure 5 is a sectional view corresponding to Figure 3, but showing a different embodiment.

In the embodiments shown in the drawings, the slide rule of the present invention is illustrated in its application to slide rules of the duplex type, but it is to be understood that some of the features thereof are applicable as well to slide rules of the familiar Mannheim type having a one-piece back.

In the embodiment illustrated in the drawings, the slide rule is provided with a slide 1 arranged to move lengthwise between spaced side rails 2 and 3. The side rails 2 and 3 are connected together by a bracket 4 at one end and a bracket 5 at the other end, said brackets in the embodiment illustrated being on the back of the rule so that the front of the rule is free of interconnections between the two side rails 2 and 3. The brackets 4 and 5 may be formed of metal such as aluminum, stainless steel, or brass, so as to be relatively rigid in the direction which restrains the rails 2 and 3 from movement which would disalign the indicia thereon. In their thickness dimension, however, the brackets 4 and 5 are relatively thin, so as to be yieldable under forces tending By so doing, spaces are provided adjacent the points of contact, and these spaces may be .are clearly visible. j "'strips 21' and 22, beyond the indicia thereon, an aper- As shown, the

ice

parallel relationship with the planar side walls 9 of the grooves 7. To take full advantage of the present invention, the opposite side walls 10 of the tongues 6 are similarly out of parallel relationship with their cooperating side walls 11 of the grooves 7.

Above and below the tongues 6, the slide 1 has shoulders 12 and 13, which cooperate respectively with shoulders 14 and 15 on the side rails. The invention contemplates that these cooperating shoulders be out of parallel relationship.

With the cooperating side walls and the cooperating shoulders out of parallel relationship, as just described, contact between the slide 1 and the rails is limited at any given cross-section to points 16, 17, 18, and 19, so that, as the slide 1 moves between the rails 2 and 3, the friction between the parts is limited to longitudinal lines of contact coincident with the four points 16, 17, 18, and

19. Between contact points 16 and 17, as well as bei tween contact points 18 and 19, a triangular shaped space is provided. Between contact points 17 and 18, a U- shaped space is provided. In the spaces just described, a y

able material, and the tongues 6 are integral with the core. At the opposite sides of the core 20, facing strips 21 and 22 are adhesively secured. The facing strips may be formed ot' Celluloid or other cellulose or plastic products, preferably white, so that the usual indicia thereon Adjacent each one of the facing ture 23 is provided in said facing strips. aperture extends entirely through the respective facing strips, so as to expose thereat the surface of the core 20. Thus an indentation in the surface of the slide is provided, which facilitates gripping by the thumb of a user and thus expedites manipulation of the slide.

As pointed out hereinbefore, the brackets 4 and 5 are relatively more yieldable in the direction which permits them to'bend about the longitudinal axis L-L of the rule, whereas they are relatively rigid against bending forces exerted in any other direction. ln cooperation with the non-parallel relationship between the side walls 8v a nd 9 of the tongueand groove, respectively, such flexibility about-the longitudinal axis L-L contributesj 'toward t'ree running of'the slide without reducing its setting retentivity. 1n the process of moving the slide 1 longitudinally between the rails 2 and 3, a force applied to the slide in the usual manner has a component, albeit small, in the transverse direction. This transverse-force component tends to bend the brackets 4 and 5 toward the position shown in dotted lines in Figure 3. The dotted lines in Figure 3 depict the bending of the brackets 4 and 5 in greatly exaggerated degree, for clarity of illustration, but it will be understood that, in practical operation, the degree of bending of the brackets 4 and 5 is a very small fraction of that indicated by the dotted lines. When the brackets 4 and 5 bend toward the position shown in dotted lines, the transverse spacing between point 16 at one edge of the slide and the corresponding point at the opposite edge increases. Likewise, the distance between points 17 at the opposite sides increases. To a lesser degree, the transverse spacing between the contact points 18 and 19 increases. Thus the slide is relatively freed of frictional drag during the process of its manipulation, but once the manipulating forces are removed, the brackets 4 and 5 resume the position shown where line contact is made at points 16, 17, 18, and 19, and sufficient grip applied thereat that the slide will retain its setting.

For use in reading the scales on the back of the slide Patented Feb. s, 1955` inga. s ightY line..` 2 6,4 Said. pane. 2.5. is, received.. withinn a.A

recess formed in the surface of bracket 5 adjacent the rails 2 and 3 and is adhesively secured to said rails so that the sight line 2.6` is properly Corelated with. the. indi'ci'a appearing on the front of the rails.

In the. embodimentI shown in Figure. 5, the. relationship of the cooperative side walls of thetongueand groove andther cooperating shouldersof the side rails and sldfes is shown in the opposite sense from that indicated. in. the other figures, but nonetheless preserving they deliberat'e angularity between the cooperating surfaces. and. con,- ning their Contact substantially to a. point in any given cross-section. In Figure 5, the groove 2.7 is dovetailed in,

cross-section, while the tongue 28.is.rectang ular, whereasV in, Figure 3, the groove 7. was rectangular and the tongue 6 a truncated triangle. In the form shown in Figure, 5',l however, contact between the side` rails. and the slide is conned substantially to points 2,9.q 3,0,` 31, and 32, as in.`

the previous, embodiment, and thev reservoir spaces.l for the. reception of` lubricant are. provided at the same. lo.- cations as in the previous embodiment, but in slightly dierent shape.

From.4 the foregoing descriptiom those skilled` in the art, should readily understand the construction and` operation of slide rules embodyingthe presentA invention and realize the advantages offered by the invention. While one complete embodiment has been described in detail, and. some alternatives. suggested, it is not to be. understood that the invention is limitedto. the. details of` the embodiments disclosed, but, on the contrary, it isI to be understood` that the embodiments. have4 been shown and described merely to illustrate the invention. Such modifications and variationsl as do not depart from the, spirit4 of'the, invention are, although not specilically described herein, contemplated by and within the scope of, the appended claims.

Having thus. described` the. invention, what isy claimed and desired, to be; secured, by Letters Patent is:

1f. In 'a slide ruley having a pair oi spaced. rails, a slide` member between, said rails and havingL a tongue-andgroove, connection therewith the in lprovement which.,

4'. The improvement of,v claim4 1 wherein the. Slide and.` rail's. havecontiguous. shoulders above` andl below the`V to.ngue-andi-groovev connection, and wherein. sald. shoul-l ders. are. cross-sectionally non-parallel' and longitudinally make line contact with` each. other.

5. The improvement of claim 1 wherein said spaced rails are. Caonrlectedm together at.. each. end. by a.. bracket..

which is resistant to bending in the longitudinal dimension of the rule and relatively yieldable in the thickness dimension thereof, said rule being free of interconnections between said rails which substantially prevent yielding of said bracket.

6. In a slide rule having a pair of spaced rails, a slide member between said rails. and having a tongue-andgroove connection therewith, the improvement which comprises, said slide-:consistingv of a core and a facing strip, saidi rails, being' connectedi together solely by brackets on only one face of the rule, said brackets. beingv relatively more yieldable about the longitudinal axis of. said rule than about any otherl axis thereof and said rails being free of interconnection which substantially prevents yielding of said brackets about the longitudinal axis of said rule, the tongue of said tongue-and-groove connection being formed on the core part of said slide. and havingv itsplanar side wall on theA side opposite said bracket in clined outwardly from saidcore toward said bracket, the groove of said tongue-and-groove connection having its sidewallon the sijde, opposite, said bracket .disposed sub.- stantiallyl parallel; with said facing` strip` soy as tomake,

' line Contact longitudinally with said inclined side wall of'said` tongue' at; the mouth off saidv groove thereby providing,` a space betweensaid side walls` inwardly of said line contact, said slide and rails having contiguous shoulders adjacent` said tongue-and-groove connection, said shoulders being non-parallel.v and` engaging only at the outer extremity thereof adjacent said facing strip thereby providing a space between` said shoulders adjacent said tongue, and said4 spaces. being packed with lubricant.

7. The improvement of claim 1`wherein said groove is of dovetail cross-section.

8^. ln a duplex-type slide rule havinga slide member andapair ofV spacedz rails supported onl opposite sides of` the slidemernber;l the improvement comprising said rails being of substantially similar shape, andfthe means supporting said railsl in proper relationship consisting.y solely of a pair of' brackets secured to the rails adjacent the ends thereofj and extending across the, slide member onV onlyfone face thereof,` saidj brackets being relatively yieldable about the longitudinal axis of, the rule in responseto manualj force andbeing relatively rigid in, any otherA axisv thereofj under; manual force.

References; Cited inthe -lcl of 'thispatent UNITED STATES RATENTS 767,117.0 Rosenthal Aug. 9, 1904.. 2,143,559 Keniel Jan. 10, 1939 2,449,954 Roberts Sept. 21, 1948 FOREIGNA PATENTS 129,533 Great Britain July 17, 1.919

5283807 France Aug. 25, 1921 901,201 France Oct. 30, 1944 

